1. Field of the Invention
The present invention relates to surgical devices, and, more particularly, to orthopaedic impactors.
2. Description of the Related Art
When performing a total hip replacement surgery, an implantable cup is required to be inserted into the acetabular cavity. The implantable cup, also referred to as an acetabular cup, is typically formed of a polymer such as polyethylene and acts as an articulating surface with the head of a femoral stem. The acetabular cup can adhere to the acetabular cavity using bone cement or by press fitting the acetabular cup into the acetabular cavity.
When a cement-less approach is used, the acetabular cup is sized to be slightly larger than the acetabular cavity and is forced into the cavity to form a tight press fit. To force the acetabular cup into the acetabular cavity, an impactor can be used. The impactor connects to the acetabular cup and has an impacting surface that a user strikes with a tool, such as a mallet, to transfer force to the connected acetabular cup and press fit the cup into the acetabular cavity. Once the acetabular cup is acceptably press fit into the acetabular cavity, the impactor is disconnected from the acetabular cup.
One possible way to connect the acetabular cup to the impactor uses corresponding threadings on the impactor and acetabular cup. The threadings are matched up and rotated so that the acetabular cup is connected to the impactor, and the reverse rotation is performed when the acetabular cup is fit in the acetabular cavity to disconnect the impactor from the acetabular cup. The threading of the impactor can be located on a rotating lever, which has a limitation on the depth of the undercut. In addition, the rotating lever uses a point contact onto the rasp undercut and has a high level of spring force.
What is needed in the art is a way to attach an acetabular cup to an impactor that can create a more secure connection between the acetabular cup and the impactor.